Photographic silver halide elements containing magenta-colored cyanforming couplers



Dec. 2. 1969 MAKQTO vos ETAL 3,481,741

PHOTOGRAPHIC SILVER HALIDE ELEMENTS CONTAINING MAGENTA-COLORED CYAN-FORMING COUPLERS Filed Sept. 9. 1965 3 Sheets-Sheet 1 OPTICAL DENSITY Q 9 N k WA VE LENGTH m n) FIG. I

OPTICAL DENSITY 9 9 N k l I I 400 450 500 550 600 650 WAVE LENGTH (mp) INVENTORS MAKOTO YOSH/DA kE/swrl: sH/aA Alf/0 cxuMuRn Walk HTNRNCYS Dec. 2. 1969 MAKOTO YOSHIDA ET AL 3,481,741

PHOTOGRAPHIC SILVER HALIDE ELEMENTS CONTAINING MAGENTA-COLORED CYAN-FORMING COUPLERS Filed Sept. 1965 3 SheetsSheet S OPTICAL DENSITY 9 .Q N 4 l l l l 400 450 500 55 0 600 650 WAVE LENGTH ('mp) FIG-.3

INVENTORS MAKo'ro YosH/M KE/SU/(E SH/Bfl my 4100- OKUMURA Dec. 2. 1969 MAKQTO vos ETAL 3,481,741

PHOTOGRAPHIC SILVER HALIDE ELEMENTS CONTAINING MAGENTA-COLORED CYAN-FORMING COUPLERS 3 Sheets-Sheet 5 Filed Sept. 9. 1965 QQQCQQ 500 550, WA VE LENGTH 500 550 600 650 WA v5 LENGTH (m u) INVENTORS IVA/(07D YOSl-IIDA KEISUKE $HI8R 4X10 OKUMURR y, ",4 W,

THE/R RTI' RNE Y3 U S e Pe U.S. Cl. 96 -100 8 Claims ABSTRACT on THE DISCLOSURE A color photographic silver halide emulsion containing a magenta-colored cyan coupler having an auto-masking action, represented-byzthe following formula:

CONHR wherein R represents a branched chain alkyl group having more than 6 carbon atoms and R represents a lower alkyl group.

The present invention relates to color photography and particularly to color photographic materials containing a cyan coupler having an auto masking action for correcting deficiencies of color regeneration of color photographic sensitive materials, said cyan coupler being used as a solution in an organic solvent. 1

Almost all of cyan couplers used as color formers for color photography are l-naphthol-Z-carboxyli'c acid derivatives or aminophenol derivatives and in the case of using these couplers in photographic emulsions, a long chain ICC droxy-2-naphthanilide colored coupler compounds having the above formula in which X is hydrogen, Y is a mononuclear aryl group substituted in a position ortho to the amide group with either halogen, alkoxy or mononuclear aryloxy groups and R is a mononuclear aryl group.

In U.S. Patent 3,034,892, are described 1-hydroxy-2- naphthamide compounds having the general formulas:

alkyl group or a dialkylphenoxy group is introduced in the molecule of the coupler as a group for endowing a difiusion-fast property to the coupler v.in order to prevent the coupler from diffusing out of alayer in which the coupler has been incorporated.

In U.S. Patent"2,449,966'and US. Patent 2,455,169 are described couplers having an auto masking action for correcting deficiencies of color regeneration of color photographic materials. H V

In U.S. Patent 2,521,908 are described 1-hydroxy-2- naphthamide colored couplercompounds having the formula:

and claims.

in which x is 0 or a positive integer from 1 to 4; y is 0 or 1; R is phenyl groups, alkyl groups having from 6 to 15 carbon atoms, alkyl-substituted phenyl groups, or

' alkyl substituted phenoxy' phenyl groups; and R is an alkyl group of 1-4 carbon atoms. However, almost all of these coupler compounds have an aryl group at the 2-position of the naphthol nucleus. While, since the introduction of an aryl group into the 2-position of the naphthol nucleus reduces the solubility of the coupler into the water-immiscible solvent of high-boiling point, such as tricresyl phosphate, dibutyl phthalate, etc. (such a solvent is called hereinafter coupler solvent), there occur troubles that the formation of dispersion of the coupler becomes difiicult and the coupler in a photographic emulsion is easily crystallized. Hence, in order to increase the solubility of the couplers, many attempts have been made. For example, there have been provided many couplers having a' dialkylphenoxyphenyl group, dialkylphenoxyalkyl group, etc., at the 2-position of the naphthol nucleus but in such couplers the structures as well as the preparation become complicated and the cost becomes very high in raw material as well as synthesis.

' It is therefore an object of the present invention to provide magenta-colored cyan couplers which have sufiicient solubility in coupler solvents and can be prepared ;by a simple method using easily available and inexpensive raw materials.

A further object is to provide magenta-colored cyan,

couplershaving a bathochromic absorption that is unexpected in view of the small chemical differences from other couplers.

Other objects will appear from the following description These and other objects are accomplished by means of this invention by using magenta-colored cyan couplers having the general formula as shown below.

wherein R represents a branched chain alkyl group having more than 6 carbon atoms and R represents a lower alkyl group.

The alkyl group represented by symbol R is, for example, Z-ethyl-hexyl group, 2 methylpentyl group, 1,3- dimethylbutyl group, 2-methylnonyl group, Z-ethyldecyl group, and the like.

The examples of the lower alkyl group represented by symbol R are methyl, ethyl, propyl, and butyl groups and the like.

A coupler having an alkyl group at the 2-position of the naphthol nucleus has in general better solubility in coupler solvents than a coupler having an aryl group at the 2- position (cf. Experiment 1). Therefore, we prepared couplers changing variously the alkyl group at the 2-position and measured about the solubility. As the result, it has been cleared that the solubility of the coupler having a dialkylcarbamoyl group is higher than the coupler having a monoalkylcarbamoyl group and further among the couplers having monoalkylcarbamoyl groups, the solubility of the coupler having a branched chain alkyl group in this invention is higher than the coupler having a straight alkyl chain (cf. Experiment 1).

However, since the maximum absorption wave length of the coupler having a dialkylcarbamoyl group is 470- 485 Nm., in a coupler solvent, that is, it is about 30 mm. shorter than that of the coupler having a monoalkylcarbamoyl group, the former is unsuitable for the color photographic materials of this invention (of. Experiment 2).

Among the couplers each having a monoalkylcarbamoyl group, the couplers having a branched chain alkyl group as in this invention shows extremely desirable absorption characteristics. That is, the maximum absorption wave length of the coupler in a coupler solvent is about 8 Nm. longer than the coupler having a straight chain alkyl group and an unnecessary short-Wave side optical density is low (cf. FIGS. 1, 2 and 4).

Moreover, in the case of the color photographic materials containing the coupler having a straight-chain monoalkylcarbamoyl group, the color image obtained is turbid, for perhaps the coupler is of low solubility and crystallized easily in the coupler solvent. Further, the maximum absorption wave length of the coupler is about 6 Nm. shorter than that of the coupler in this invention having a branched chain alkyl group and the D /D ratio (the ratio of blue filter optical density to green filter optical density) is about 40% larger than that of the coupler to be used in this invention (cf. Examples 1 and 2).

From these facts, it may be understood that the coupler in this invention is a very excellent coupler having very desirable properties for being used as color photographic materials. The coupler in this invention further has the merit, as will be stated below, that it can be produced by 2 steps of a simple synthesis using as the raw material easily available and inexpensive monoalkylamines having a branched chain group such as Z-ethylhexylamine,

A 4 As the couplers to be used in this invention, there are, for example,

CONHCHz'CH(CH2) 2CH CH3 I N=N/ C-ONHCHCH2CHCH3 CH3 CH I COOC4H0 (H) CONHCH2(|3H(CH2)3CH;

' Q N=N 000011;; (III) CONHCHZ(IJH(CH2)QOH OOCaHs CONHCH:CH(CH2)6OH3 I Ha I N=N COOCiHi CONHCH2CH(CH2)7 H 0:115 Q N=N ooooHi v1 CONHCH2$H(CH:)3CH3 C2H5 Q N=N oo0oiH1 VII The couplers in the present invention were prepared as follows:

( l-a) 2- (N-Z-ethylhexylcarbamoyl) -l-naphthol In a 300 ml. flask, a mixture of 132 g; of l-hydroxy- 2-naphthoic acid phenylester and 65 g. of 2-ethylhexylamine was heated. After distillingoff resultant phenol, the reaction mixture was'cooled to room temperature, and addedwith a small amount of petroleum ether. The resultant precipitate was collected by filtration and washed with 300 ml. of petroleum ether. A yield of 131 g. (83%) was obtained. The melting point of the product was 60- 61 C. The elementary analysis value was N, 4.52%; C, 76.09% and H, 8.53%. (Calculated value N, 4.68%; C, 76.25% and H, 8.37%.)

( l-b) 2- (N-Z-ethylhexylcarbamoyl) -4-( Z-carboethoxyphenylazo)-1-naphtho1 (Formula IV) 18 g. of Z-carboethoxy aniline was suspended in a mixture of 30 ml. of water and 30 ml. of concentrated hydrochloric acid, and 9 g. of sodium nitrite dissolved in 15 ml. of water was added at a temperature below 5 C. The diazonium solution was added to a solution containing 30 g. of 2-(N-2-ethylhexylcarbamoyl)-1-naphthol in 400 ml. of pyridine at a temperature below 8 C. The resultant precipitate was collected by filtration,v washed with 1000 ml. of water containing 50 ml. of concentrated hydrochloric acid, and. then 2000 ml. of water. After recrystallization from 800 ml. of ethanol, a yield of 39 g. (82%) was obtained. The melting point of the product was 140-142 C. The elementary analysis value was N, 8.79%;C, 70.66% and H, 6.90%. (Calculated value N, 8.85%; C, 70.74% and H, 6.9 5%.)

I A 2- (N-2-ethylhexylcarbamoyl) -4-( 2-carbomethoxyphenylazo)-l-naphthol (Formula III) The above compound was obtained in the same way as in (l-b) using 2-carbomethoxy aniline insteadvof 2- carboethoxy aniline. The, yield was 76% and the melting point of the product was 138140 C. The nitrogen analysis value was 9.15% (calculated value 9.12%).

2-(N-Z-methylnonylcarbamoyl)-4-(2-carboethoxy- .phenylazo)-1-naphthol (Formula V) 2-(N-2-ethylhexylcarbamoyl)-4-(2 carbopropoxy phenylazo)-1-naphthol (Formula VI) In (1-b) using 2-carbopropoxy aniline was used instead of 2-carboethoxy aniline to give the above objective compound. The yield was 41%, the melting point was 121-123" C., and the nitrogen analysis value was 8.65% (calculated value 8.59%).

Several experiments were conducted to compare the properties of the coupler in this invention with the comparative couplers having thefollowing formulas.

(I)CH (JoNHomoHwmnom 000cm, (A)

' ooNHwrmuom 000cm. I (B) mmommom l N=N COOCzHa (O) CON(CH:(|H(CH:)3CH3)3 CgH5 JOOCzHu (D) on CON(CH2CH2CH(CH3)2)2 l N=N COOCZHE (E) EXPERIMENT 1 An excessive amount of the coupler in this invention shown by Formula IV and excessive amounts of comparative couplers (A), (B), (C), (D), andv (B) were dissolved by heating to 60 C. in tricresyl phosphate respectively while stirring, thus obtained solutions-were kept at 35 C. while stirring, and the amount of the coupler dissolved in the saturated solution was measured spectroscopically. The measured solubilities of the couplers are shown in the following table as mol ratios.

' Molratio I M.P. of Nitrogen analysis Formula i of solucoupler Substituent at 2-p0sition of naphthol nucleus of coupler bihty C.) Found Caled. Alkylcarbamoyl group having a branched chain IV -142 8. 79 8. 85 .Arylcarbamoyl group. L. I. A 1. 8 237-238 8.80 8. 98 Monoalkylcarbamoyl group B 28. 2 140-142 7. 87 7. 93 .123 1% 28% 33113 3'22 iii Di lcarbamo l mu D0- -zn uu? 106 153-155 8. 25 8. 35

I Used in this invention.

That is, it is clear from the results that the coupler to be used in this invention is dissolved in a coupler solvent far better than the coupler having an arylcarbamoyl group at the 2- position of the naphthol nucleus and the coupler having a monoalkylcarbamoyl group at the position.

EXPERIMENT 2 A given amount of each coupler of Formula IV and Formula B was dissolved in tricresyl phosphate and the absorption spectrum was measured in each case. A compound having the azo structure of 4-arylazo-1-naphthol series generally has two maximum absorption in a visible region and hence in this experiment the longer side maximum absorption curve of each coupler is shown in FIG. 1 drawn to make the maximum optical density to 1.0. Similarly, the absorption curves of dibutyl phthalate are shown in FIG. 2.

Also, the absorption curves of couplers (D) and (E) in tricresyl phosphate are shown in FIG. 3.

As shown in these curves, the longer side absorption maximum of the coupler to be used in this invention is in about 8 Nm. longer than that of comparative coupler (B) and the short side optical density of the former is lower, which show the chemical structure of the long side absorption spectrum being large. Couplers (D) and (B) have two carbamoyl groups each, however the longer side maximum absorption is disappointedly in an extremely shorter wave length side.

These phenomena are further emphasized by using a specific solvent such as dioctylbutyl phosphate and the absorption curves of the couplers in the solvent are shown in FIG. 4 and FIG. 5.

EXPERIMENT 3 One gram (1 g.) of coupler (IV) in this invention was dissolved in 10 ml. of tricresyl phosphate at 60 C. with stirring and kept at C. In this case, the crystallization begun after about 10 minutes. While, when 1 g. of comparative coupler (B) was dissolved in ml. of tricresyl phosphate with stirring at 80 C. and kept at 60 C., the crystallization begun after about 2 minutes.

That is, the crystallization of the coupler to be used in this invention in a coupler solvent is extremely diflicult as compared with that of the comparative coupler.

The invention will further be explained by the following examples.

Example 1.Into 10 parts of tricresyl phosphate was dissolved 1.25 parts of coupled (IV) with stirring at 80 C., and the solution was added in 100 parts of an aqueous 10% gelatin solution that had been preliminary heated to 60 C. Two parts of an aqueous solution of 10% sodium alkylbenzene sulfonate was added and dispersed with mixing by means of a high speed mixer for 5 minutes at 65 C. followed by stopping the stirring for 1 minute. This was repeated 5 times to give a dispersion of the coupler.

Into 100 parts of a red-sensitive silver iodobromide emulsion was added 13.5 parts of the above dispersion with stirring at C. and coated on a film support and dried to give a red-sensitive color photographic material.

The above procedure was repeated using comparative coupler (B) instead of coupler (IV) to give dispersion. In this case, the temperature at which the coupler was dissolved in the coupler solvent has to be strictly maintained at temperatures higher than 80 C. and the temperature of the aqueous gelatin solution at the emulsification had to be strictly maintained at temperatures higher than 70 C. From thus obtained dispersion, a red-sensitive color photographic element was obtained in the same way as above.

Thus prepared two color photographic sensitive films were exposed to red light using an optical wedge and then subjected to usual color development by using the following color developer.

8 Color deveolper: G. N,N-diethyl-para-aminoaniline sulfate 2.0 Sodium sulfite 2.0

Sodium carbonate (mono-hydrate) 50.0 Hydroxylamine hydrochloride 1.5 Potassium bromide 1.0 Water to make 1,000 ml. (pH 10.8 0.1).

Thus developed photographic films were bleached and fixed using the bleaching solution and the fixing solution showing the following formula respectively to remove the undeveloped silver halide and thus reduced silver.

Bleaching solution: G. Potassium ferricyanide 100 Potassium bromide 20 Water to make 1,000 ml. (pH 6.9 0.3). Fixing solution:

Sodium thiosulfate g 200 Sodium sulfite g 20 Acetic acid (28%) ml 45 Boric acid ga 7.5 Potassium alum g 20 Water to make 1,000 ml. (pH 4.5 0.2).

From the color photographic film were obtained simultaneously a cyan-colored negative image and a red positive image consisting of the unreacted remaining coupler, and the transparency of the film was very excellent and the red positive image exhibited sufiicient red.

On the other hand, a cyan-colored negative image and an orange positive image obtained from the color photographic film containing comparative coupler (B) were hazy and a little opaque, owing to the partial crystallization and the lower dispersibility of the comparative coupler. And moreover, the positive color image is more hypsochromic than the positive image of the this invention.

The maximum absorption wave lengths of the films obtained by bleaching and fixing the two color photographic film as above were measured and the results are shown in the following table.

Maximum ab- Ratio of (B) to V sorption wave (I Coupler length, Nm. in (D B/DG) (IV) 510 1. 00 (B) 505 1. 39

SOsN.

was added into thus prepared emulsion and dispersed therein by stirring using a high speed rotary mixer for 20 minutes at 65 C. followed by adjusting the pH to 7.0 with the addition of citric acid to give a dispersion of the couplers.

Separately, 0.8 part of comparative coupler (B) was dissolved in 10 parts of di-n-butyl phthalate at C. with stirring and the above procedure was repeated using parts of an aqueous 10% gelatin solution and 16 parts of a 5% aqueous alkaline solution of cyan coupler (F) to give a dispersion of the couplers.

Into 100 parts of a red sensitive silver iodobromide emulsion was added 10 parts of the dispersion of the coupler (IV) and 17 parts of the dispersion of the coupler (B) respectively, and two color photographic materials were prepared in the same way as Example 1.

Two color photographic materials were exposed to redlight using an optical wedge, color-developed, bleached, and fixed as in Example 1, cyan-colored negative images and red or orange positive images were obtained at the same time. The film obtained by using coupler (IV) has very excellent transparency, while the film using coupler (B) was hazy and opaque. The difference between them was larger than the case of Example 1.

The maximum absorption wave lengths of thus processed films were measured. The results are shown in the following table.

Ratio of (B) to (IV in (DB/D6) Coupler Example 3.By repeating the procedure as in Example 1 using coupler (III), a red-sensitive color photographic material was obtained. The film was exposed to red light and treated in the same way as Example 1 to give a cyan-colored negative image and a red positive image at the same time. The transparency of thus treated film was very excellent and the red positive image exhibited sufficient red.

Example 4.By repeating the procedure as in Example 1 using coupler (I), a red-sensitive color photographic film was prepared. The film was exposed to red light and treated in the same way as in Example 1 to give a cyan-colored negative image and a red positive image at the same time. The transparency of thus treated film was very excellent and the red positive image exhibited sufiicient red.

What is claimed is:

1. A color photographic silver halide emulsion containing the coupler having the general formula CONHR 3. The color photographic silver halide claimed in claim 1 wherein said coupler is emulsion C ONHCHCHaCHCH;

H; CH

JJOOCHs 5. The color photographic silver halide emulsion as claimed in claim 1 wherein said coupler is 6. The color photographic silver halide emulsion as claimed in claim 1 wherein said coupler is ONHCHBCH(CHQ)CH3 7. The color photographic silver halide emulsion as claimed in claim 1 wherein said coupler is CONHCH2CH(CH2)7CH3 COOCH:

8. The color photographic silver halide emulsion as claimed in claim 1 wherein said coupler is References Cited I. TRAVIS BROWN, Primary Examiner 

